Development of an intravascular impedance catheter for detection of fatty lesions in arteries

Recent studies show that the presence of fatty lesions in the atherosclerotic vessel wall is a risk factor for acute occlusion of blood vessels. Although fat has a high electrical resistivity, existing impedance catheter systems cannot be used for detection of these lesions because artefacts owing to deviating impedances from the extravascular surroundings have a major and irretraceable effect on the measurement. Standard algorithms used in attempts to compensate for these artefacts suffer from severe instability problems. We developed a new Intravascular Impedance Catheter (IIC) system using a differential measurement procedure, which makes the measurement insensitive for the extravascular surroundings. With this IIC, we performed experiments on human carotid and iliac arteries from the section ward, showing that plastic models of arterial fatty lesions (8 mm³) can be detected reliably